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The muscular engine can use multiple fuels.

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The muscular engine can use multiple fuels.

To improve the functioning of your muscles,
choose well your diet!

During exercise, muscle burns sugar as well as fat and sometimes proteins.

Sugar consumed by motor muscle is glucose. Glucose links are grouped into huge chains called glycogen. This large structure is the sugar storage form in the liver and especially in muscle.

Fat burned in muscle is comprised of fatty acids. They are grouped by three and hook onto a small molecule, the glycerol to form the "triglycerides". These are a little in reserve in muscle. But most of the stock is at a distance, in fat cells in fatty tissue.

The proteins used by the muscle masses are amino acids. They are grouped together in large molecules: proteins. These structures are chemical plants from the cell or form the muscle fibers. Each protein fulfilled a function in the muscle and it does not really exist in the form of storage.

Take stock of inventory!

The glycogen contained in muscles is limited. In athletes of leisure, they are exhausted after about 60 to 90 minutes of running. After a hard training and appropriate eating behavior, they allow for an entire marathon at a good pace. Conversely, grease stocks are inexhaustible. Indeed, even among the most slender of athletes, its thin layer of grease bring energy to run about 700 kilometers!

Exhausting his stock of sugar is hit the "wall"!

The failure on endurance events most often comes from the depletion of glycogen stores. Indeed, fats are burned in the presence of sugar as a glucose derivative involved in the burning of fatty acids. So when the muscle sugar reserves are empty, the engine stops: the "marathon of the wall." This mishap often occurs in the neophyte and the experienced runner trap sometimes. As during a petrol car, all is well until the tank is empty. In a few meters, the wake becomes chaotic. The muscles stiffen and suffer pain or cramps. This sudden failure glue runner bitumen. After the 30th or the 35th kilometer, you can see those who have not enough stored glycogen. They walk on the roadside or trot painfully. They try to stretch or drink energy drinks. Nothing worked ... They look at their watch and stopwatch are in suffering, mourning this performance as expected! Yet they have much ingested a little starchy but they have not read a good book explaining how to optimize their supply before the test!

How to train to avoid the depletion of reserves?

Beyond nutrition, amply developed in the heart of this book, there are some simple rules to limit the depletion of glycogen stock and reduce the risk of default on long trials.

- In trotting, walking or pedaling at a moderate intensity, without being out of breath, muscle learns to use more fat. The mixture used contains more fatty acids and less glucose. That spares glycogen stores.

- When running or pedaling to medium, perceiving a slight increase in respiratory rate, body gradually empty glycogen stores. In response, he learns to increase its stock.

- Running or more pedaling at higher intensity, ultimately shortness of breath, the body learns to less lactic acid. Thus, each glucose is burned more completely and combustion provides 19 times more energy! Again, this chemical adaptation saves glycogen.

Each session is aimed at soliciting one of the limiting factors of performance. Again, this is a varied workout that is useful.

Sugar liver and muscle sugar: to each his mission!

Glucose from the liver to the blood and brain!

liver glycogen reserves only serve to maintain a constant level of glucose in the blood and avoid hypoglycemia. Indeed, the brain is known to use as sugar and its operation requires continuous availability of this precious substance in the blood. Also, to optimize the functioning of the nervous system, glucose he penetrates very easily and freely in neurons. However, it hardly goes into the muscles because it must cross the cell membrane by slipping into channels that limit the speed of passage. Clearly, the glucose in the liver but also that provided by energy drinks during the event, does not bring a lot of energy to the muscles, it can not compensate for the depletion of intramuscular glycogen reserves, it does comes not treat the "marathon of the wall." The glucose in the liver and drinks you can avoid hypoglycemia but it contributes only moderately to muscle contraction.

Glucose muscle for muscle contraction!

The specialization of sugar storekeepers organs finally has a few advantages. You understood, through this regulation, physical activity rarely causes hypoglycemia and brain defects. But you also discover that the intramuscular glycogen does not help regulate sugar levels in the blood. In contrast to liver cells, muscle fibers lack the enzyme for the glucose output. Thus, the sugar stored in the muscles is reserved for the sport! It accumulates quietly until the next effort. By ingesting carbs right after training or in the days preceding a competition, you actively store glycogen and you keep it for your next exercise. So do not hesitate, you can eat copiously "sugars" for the 3 days prior your marathon, time spent at rest will cause reduction of reserves!

Use protein for energy,
it is heat the house by burning the furniture!

Proteins are made available to the body to make energy that near exhaustion. Wait until the discharge body, corticosteroids, potent stress hormone capable of stimulating the destruction of proteins. Indeed, as you know, there are no storage protein shape and use of amino acids for energy means start a carnage in muscle cells! We must break down the muscle fibers! It must burn enzymes for chemical reactions! It is understood that the body can program this possibility last resort. This process begins if you insist especially after hitting the "wall of the marathon." In these circumstances, chemical aggression is associated to mechanical attacks every stride to cause unbearable aches tomorrow. Cell damage is major because all amino acids can not be transformed into glucose and provide energy. It is sometimes necessary to crush a protein to get some amino acids able to burn easily! To limit the "proteolysis" or "protein destruction" during exercise, you need to put enough sugar available in muscle glycogen stores up and making a glucose drink throughout the test. A protein intake during the previous meal the start, especially in the form of reduced dairy, would also be effective. Some scientists believe it may be beneficial to propose, during the year long-term, small proteins containing amino acids called "branched" easily converted into glucose.

Glucose is the "super" fat is the "diesel".

A glucose molecule contains six carbon atoms, 12 carbon hydrogens and 6 oxygen atoms. The presence of the latter that makes you understand that this sugar is already slightly oxidized! A fatty acid substantially contains only carbon and hydrogen. So it takes a lot less oxygen to burn glucose as fatty acids! Thus for the same work the heart and lungs, for the same consumption of oxygen, glucose provides 1.5 times more energy than fat.

You understand why, on high, when the body begins to lack oxygen, muscles preferentially consume glucose. However, when the activity is more moderate, cardiovascular system provides enough oxygen and muscle can consume more fat. Clearly, when you run the 10,000 meters you type only in glycogen stores. However, during a walking tour, you consume a maximum of fat. Half way, if you want to do a good time on marathon, you consume a mixture of sugar and fat whose proportions depend on your talent for endurance, your training, your diet and the status of your reservations!

Your ability to use fat is very dependent on your genetic makeup. Indeed, if nature has given to the muscles of a person enough specialized enzymes in burning fat, he manages to save his glycogen. You know also an endurance athlete able to run for hours without stopping while never consume starchy. Go think ... This is the dog sled or Yuschi! These marathoners ice do not enjoy any cereal crop on the ice and just eats oily fish!

Fat is well worth!

You know, the glucose has a higher yield fat. By consuming much oxygen, more energy is obtained by burning sugar in concommant fat. At the same heart rate, it runs faster if the mixture used is rich in glucose. However, this fuel has two drawbacks. First, the tank is limited: to roll back "wall", the body is forced to use a mixture of sugar and fat. Second, store glycogen significantly increases the athlete's body.

Sugar is a "hydrophilic" substance, "loves water" and dissolves easily. Your sugar dissolves completely in your coffee, each glucose molecule creates electric links with many water molecules that allow it to remain suspended in the liquid. The same happens in your muscles. Thousands of glucose links interconnected as glycogen are bonded to a plurality of water molecules. Finally set aside for 1 gram of sugar, it is necessary to store water and 3 grams heavier body than 4 grams. As 1 gram of sugar provides 4 kilocalories, carbohydrate transported each kilocalorie weighs 1 gram.
Conversely, the fat substance is a "hydrophobic". She "does not like water." Water and grease do not mix and whipped cream floats on irish-coffe. Fatty acids are stored in fat cells in the form of droplets substantially free of water. As one gram of fat provides 9 kilocalories, each kilocalorie transported lipid weighs 1/9 of a gram or 0.11 grams. Sugar is 9 times heavier than fat. So take a race with solid reserves to the brim makes you take 3 to 4 kilos. And even if they disappear gradually throughout the test, you will carry them. If you do not totally deplete your stock you conveyed unnecessary kilos!
Your athletic body is comparable to a Formula 1. Do not overload the meteor with an excess of gasoline. Do not cross the line with gallons of unused fuel. Better manage pit stops and finish the race dry tank. Ideally, the marathon runner must hit the "wall" passing under the banner "arrival".

How to increase the use of fat?

You understand, do not abuse the glycogen stock! Therefore, it is necessary to learn how to burn fat. The long trips to moderate intensity, including cycling, found here an excellent indication.

You know the "sugars" tend to turn into fat. At the diligent athlete, it seems that the triglycerides from the "sugars" preferentially store in the muscles in the form of micro-droplets. These fatty acids reserves would be more easily mobilized for muscle contraction that located far away fat in fat cells. Also, can the regular sports enjoy a little indulgence deal with sweets. Even turned into fat, sugary products appear to contribute to endurance performance.

In contrast, a high-fat diet has not proved effective in increasing the proportion of fat consumed with exercise. Eating too much fat can not save glycogen, or back the "Wall of the marathon." A study in Alpine Hunters attempted to assess the interest of a fat intake during exercise to save the sugar reserves. These soldiers were to reach the top of a mountain. Half of the workforce enjoyed a drink of traditional sweet effort. The other group was fed with "TCM" or "medium chain triglycerides" fat supposedly digestible. Obviously the "sweet group" won the event! The other hit the "wall" and have experienced nausea! Indeed, the ability to consume fat does not depend on the amount of fatty acids available but the equipment in "Enzymes fat burners" present in the muscle cell.

Being overweight does not appear to increase the use of fat. If you are the victim of excess weight if you exercise to lose weight, you can not deny yourself completely starchy if you want to lose weight through physical activity ...

Doctor St├ęphane CASCUA. - 18 f├ęvrier 2010.

Conflicts of interest: the author or authors have no conflicts of interest concerning the data published in this article.


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